<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Title</title>
</head>
<body>

</body>
<script>
	var obj = {};
	Object.defineProperties(obj,{
		age:{
			value:10,
			enumerable:true,
			writable:true,
			configurable:true
		},
		userName:{
			value:"zhangsan"
		}
	})
	delete obj.age;
	console.log(obj);
	
</script>
</html>